Method of dry cleaning



Feb. 12, 1935.

P5EEV0IE SOLVNT TANK A. E. HATFIELD 1,990,691

METHOD OF DRY CLEANING Filed NOV. 25, 1933 WASHER IN VENTOR A. 5. k/afl'le/a ATTORNE Patented Feb. 12, 1935 UNITED STATES PATENT OFFICE METHOD OF DRY CLEANING Arthur Edward Hatfield, Toronto, Ontario, Canada My invention relates to a method of dry cleaning, that is, a process of cleaning garments, fabrics, textiles and the like, by means of solvents such as light hydrocarbons, including gasoline,

l naphtha, carbon tetrachloride, trichlorethylene and the like.

In United States Patent 1,728,342, in which myself and Eustace Alexander Alliott are joint inventors, a soap solution for use in dry cleaning is disclosed. Dry cleaning fluids do not remove water soluble soils comprising largely starches and sugars. To efliciently clean garments not only greasy soils but also starch and sugar soils must be removed. In my Patent 1,728,342 I disclosed that water must be incorporated with the soaps to assist in the removal of water soluble stains which would otherwise be left untouched by washing in dry cleaning fluid.

Soap itself has some power of dispersing water through dry cleaning fluids. It is disclosed in my former Patent 1,728,342 that a stabilizing agent should be used with the soap in order to produce a stable emulsion of the water and dry cleaning fluid. The stabilizing or dispersing agents disclosed in my previous Patent 1,728,342 are fatty acids, chlorinated hydrocarbons such as pentachlorethane, trichlorethylene, and perchlorethylene. The dispersing or stabilizing agent disclosed to be themost preferable because of its high emulsifying property is cyclohexanol.

While the dispersion of water aids in the removal of water soluble soils, difliculty was experienced in emulsions formed with the matter extracted from the soiled fabrics, rendering it necessary to use various chemical methods of clarification in order to render the solvent suitable for subsequent distillation and reuse, due to the fact that certain soils are within the boiling range of the solvent.

United States patent to Warren T. Reddish No. 1,911,289, discloses a process of dry cleaning in which water is dispersed throughout the dry cleaning fluid by means of a dispersing agent and the fabrics cleaned with the resulting emulsion. The Reddish patent uses, in formula '7, the dispersing agentI have disclosed in my Patent 1,728,342. The dispersing of water through a dry cleaning fluid having been taught in Patent 1,728,342, the novelty of the Reddish process lies in the limiting of the quantity of water present in the dry cleaning fluid. It will be noted that Reddish takes particular pains that the water dispersed does not exceed the moisture tolerance of the fabrics. This is more or less necessary because an excess of water would result in the formation of water spots. This is due to the fact that the fabrics always absorb substantially all of the moisture in the cleaning solvent. While the moisture is uniformly dispersed throughout the cleaning solvent no spotting will occur. After the moisture tolerance has been reached, an excess of moisture will result in spots, streaks, and "grey whites.

One object of my invention is to provide a novel process of dry cleaning garments and fabrics in which both water soluble and non-water soluble soils are removed.

Another object of my invention is to provide a process of dry cleaning in which water is dispersed throughout the cleaning fluid and in which the quantity of water is not critical.

Other and further objects will appear from the following description.

In general, my invention contemplates the washing of garments, fabrics and the like. by means of a dry cleaning fluid in which waxes and oils have been dispersed to remove all greasy soils together with those soils which might be.

redeposited on fabrics in the presence of moisture. The presence of dispersed waxes and oils renders the fabrics substantially water repellant. In a later stage of the process water is dispersed through the solvent which is continuously being filtered in a cyclic process. The water then removes the water soluble stains. The quantity of water is not critical because fabrics have been made substantially water repellant.

The accompanying drawing is a diagrammatic view of one form of apparatus capable of carrying out the process of my invention.

A dry cleaning solvent such as naphtha, gasoline, carbon tetrachloride or trichlorethylene and the like, is pumped from tank 1 through line 2, through pump 3, through filter 4, through adapter 5, through line 6, to the washer 7, it being under stood that valve 8 to the suction side of the pump is open. Cover 9 of the adapter 5 is opened and a solution consisting of waxes and oils and a dispersing agent are introduced into the streamof solvent passing to the washer. This solution may consist of paraflin wax, glycerides of the various acids of higher molecular weight and a dispersing agent such as ethylene glycol, mono-butyl ether. A typical example of a solution is as follows:

Parts by weight Paraffin wax 30 Castor oil 30 Cocoanut oil 30 Ethylene'glycol mono-butyl ether 10 The above example is merely one formula and is given by way of example, and is not to be construed as a limitation. The wax and oil solution is added to the dry cleaning fluid to an extent of about,l0% so that the dry cleaning fluid will consist of cleaners solvent and 10% of the wax oil solution. When a sufficient quantity of solvent waxfat mixture has been supplied to the washer 7, the pump 3 is stopped, the cover 9 is secured and the garments, fabrics and the like to be cleaned, are placed in the washer through the cover thereof. The cover is then secured and the pump 3 started. The solvent, including the wax fat mixture, then circulates from the washer through line 10, through sight glass 11, through strainer 12, through pipe 13, to pump 3, through pipe 14, through filter 4 and back to the washer. The strainer catches buttons, coins, pins and the like, and prevents them from reaching the pump or the filter.

The soil removed by the solvent is deposited upon the leaves of the filter 4. The rate of flow is maintained at a rapid rate and the solvent from the filter returning to the washing machine is observed through sight glass 15. The washing is continued until the sight glass shows that the solution returning to the machine is entirely free of dirt. This may be determined further, by bleeding a part of the circulating stream of cleaning fluid through line 17, which is controlled by valve 16. When it has been determined that the solution is free of all suspended matter, valve 18 is opened permitting a mixture from reservoir 19 to fiow through line 20' to the suction side of the pump 3. Reservoir 19 contains a mixture comprising three parts of water, one part of alcohol, and a filter aid. The filter aid comprises a diatomaceous earth of light specific gravity. The salient element of the liquid in reservoir 19 is water. Filter aid may or may not be used as desired. If desired, additional dispersing material may be used with the water. Triethanolamine, anhydrous propyl alcohol, anhydrous methyl alcohol, anhydrous aryl alcohol, cyclohexanol or the like may be used. It is to be remembered that valve 18 is not opened until it is determined that the solvent circulating in the first stage of the process is clear of suspended matter. The suspended matter will be redeposited upon the fabrics in the presence of an excess of moisture thus causing water spots, wrinkles and the like, as well as the greying" of whites. It will be observed that the presence of the wax oil mixture renders the fabric of the material being cleaned substantially water repellant. The amount of water added in the second stage of the process, therefore, will be immaterial. The circulation is continued with the dispersed water in the solvent, the water washing the water soluble stains from the fabrics. The adding of water at the suction side of the pump causing it to pass through the filter permits it to pass to the washer in a very fine state of di..- persion. The circulation of the solvent plus the added water is continued until the solvent becomes clear, which will indicate that the soil has been deposited on the leaves of the filter.

At this time substantially all of the water will have been absorbed by the porous matter on the filter leaves or deposited upon the surface of the fabric, so that the solvent will be substantially free of water. Due to the fact that the fabrics are rendered substantially water repellant, there is very little absorption of the water by the fabric. I am thus enabled to use a very small percentage of water which, as pointed out below, usuallyruns about 1% of the solution. This small quantity of water will readily be absorbed by the filter cakes on the filter leaves and thus removed from the solution. The pump is then stopped and the clothes are removed from the washer and treated in a manner well known to the art, that is, the excess solvent is centrifugally extracted and the clothes dried in any suitable manner.

It will be seen that due to the fact that the fabric is given a water repellant property in the first stage of the cleaning operation, the water added in the second stage does not penetrate nor have any deteriorating effect on the material, such as causing the cloth to shrink or wrinkle. The water acts only on the surface of the cloth to remove water soluble materials or stains.

Due to the fact that the dirt removed from cloth has a tendency to form slimes on the leaves of the filter which would tend to clog the filter and thus slow operation of the process, I include a filter aid in the second stage of the process.

This tends to cause the dirt to form a porous mass on the filter which does not hinder-the passage of the cleaning material through the filter.

In general, I have found that approximately 1% of water is sufficient inasmuch as none of the water is absorbed. It will be understood, however, that the quantity of water is not critical and may be used to any desired extent, depending upon the type of garment being cleaned.

In order to secure maximum efficiency, it is preferable to grade the work prior to cleaning by sorting the very dirty articles from those which are moderately clean. It is obvious that there is not the same necessity for moisture upon a moderately clean garment as there is upon one which is badly soiled. With moderately clean garments, a very small quantity of moisture will suffice. 7

After a cleaning solution has been in continuous use for a time, it takes up slight traces ofcoloring matter from the fabrics and becomes darkened in color as a result of the fatty matter, decomposed food stuff and the like extracted from the fabrics. When this occurs the solution may be decolorized by means of decolorizing carbon or the like.

It isto be understood, of course, that my process may be practiced in two separate stages. One washer may be used for the preliminary cleaning and impregnating step. The impregnated and water repellant fabrics may then be removed to another cycle in which a solvent containing water is employed.

It will be seen that I have accomplished the objects of my invention. I am enabled to remove both the oil soluble and water soluble soils from fabrics. I am enabled to render the fabrics substantially water repellant so that moisture will not be absorbed in the second stage of the process in which a solvent containing moisture is employed.

Clothes cleaned by means of my process are completely restored and immaculate. Woolen garments are given new life due to the fact that ordinary cleaning processes tend to remove the natural wool fats and oils present. This tends to age woolen fabrics and destroy their life. The fabrics become dull and the garments do not hold their shape when pressed. Woolen garments cleaned by means of -my process are not only clean, but new life is given to the garments with the result that they are enabled to hold their press and look as good as new.

It will be observed that I introduce moisture into the clarified solvent during the second stage of my process at the suction side of the pump. Thus the pump acts to thoroughly incorporate the moisture in an even manner throughout the solvent. If desired, I may incorporate the moisture by means of a viscolizer or an homogenizer, thus mechanically dispersing moisture, in which case no. dispersing agent of a chemical nature need be employed.

The addition of my wax-oil'mixture has an additional advantage of replacing the dressings and spinning oils, which are used in the weaving of the cloth. Ordinary processes of dry cleaning remove these dressings. My process insures that they are not removed and if lacking due to prior cleaning by other methods, these oils will be replaced by my process. A garment cleaned with my process not only is rendered water repellant, but is given a higher sheen and is enabled to hold its shape after finishing. This better finish and sheen is an important feature of my process.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of my claims. It is further obvious that various changes may be made in details within the scope of my claims without departing from the spirit of my invention. It is, therefore, to be understood that my invention is not to be limited to the specific details shown and described.

Having thus described my invention, what I claim is:

1. A process of dry cleaning including the steps of washing a fabric in a solvent containing a glyceride of a fatty acid unaccompanied by a substantial amount of the saponified glyceride whereby the fabric is rendered water repellent and then washing the fabric with a solvent containing water. I

2. A process of dry cleaning including the;

steps of washing a fabric in a solvent containing castor oil unaccompanied by a substantial amount of saponifled oil whereby the fabric is rendered water repellent, and then washing the fabric with a solvent containing water.

3. A process of dry cleaning including the steps of washing a fabric in a solvent containing cocoanut oil unaccompanied by a substantial amount of saponified oil whereby the fabric is rendered water repellent, and then washing the fabric with a solvent containing water.

4. A process of dry cleaning including the steps of washing a fabric in a solvent containing a wax and castor oil whereby the fabric is rendered water repellent, and then washing the fabric with a solvent containing water.

5. A process of dry cleaning including the steps of washing a fabric in a solvent containing a wax and cocoanut oil whereby the fabric is rendered water repellent, and then washing the fabric with a solvent containing water.

6. A process of dry cleaning including the steps of washing a fabric in a solvent containing a paraffin wax, a vegetable oil and a dispersing agent whereby the fabric is rendered water repellent, and then washing the fabric with a solvent containing water.

'1. A process of dry cleaning including the steps of washing a fabric in a solvent containing parafiin wax, vegetable oil and ethylene glycol mono-butyl ether, whereby the fabric isrendered substantially water-repellant whereby the fabric is rendered water repellent, and then washing the fabric with a solvent containing water.

8. A process of dry cleaning including the steps of washing a fabric in a solvent containing a vegetable oil whereby the fabric is rendered water repellant, and then washing the fabric with a solvent containing water.

9. A process of dry cleaning including the steps of washing a fabric in a solvent containing vegetable oil and a wax dispersed therethrough and subsequent washing the fabric with a solvent containing water.

10. A continuous process of dry cleaning including the steps of circulating a solvent containing a wax and a vegetable oil through a washing stage and a filtering stage whereby fabrics in the washing stage are cleaned and rendered substantially water repellant, then adding water to the circulating stream of solvent to remove water soluble soil from the fabric.

- 11. A continuous process of dry cleaning including the steps of circulating a solvent containing a wax and a vegetable oil through a washing stage and a filtering stage whereby fabric in the washing stage is cleaned and rendered substantially water repellant, then dispersing water and a filter aid through the circulating stream of solvent.

12. A continuous process of dry cleaning including the stepsof washing fabric in a solvent containing a material capable of rendering the fabric water repellant, filtering the suspended soil from the solution, then dispersing water through the solution, washing the fabric and filtering the solution and continuing the washing and filtering steps until the dispersed water terial capable of rendering the fabric water re- 1 pellant is added to an extent of substantially 10% of the solvent.

16. A method as in claim 13 wherein the water dispersed through the solvent comprises about 1% of the solvent.

17. A method of dry cleaning including the steps of dispersing a wax and a vegetable oil through a dry cleaners solvent, circulating the solvent through fabric, continuously filtering the solvent, continuing the circulating and filtering steps until the solvent is substantially filtered of soil, then dispersing a small quantity of water through the solvent, continuing the circulating and filtering steps until the water is substantially removed from the solvent, removing the fabric and drying the same. r

18. A process ,of .dry cleaning steps of washing fabric in a solvent containing a material other than the solvent capable of rendering the fabric water repellent and then washing the fabric with an organic solvent containing water.

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